diff options
Diffstat (limited to 'node_modules/emittery')
| -rw-r--r-- | node_modules/emittery/index.d.ts | 432 | ||||
| -rw-r--r-- | node_modules/emittery/index.js | 408 | ||||
| -rw-r--r-- | node_modules/emittery/license | 9 | ||||
| -rw-r--r-- | node_modules/emittery/package.json | 66 | ||||
| -rw-r--r-- | node_modules/emittery/readme.md | 409 |
5 files changed, 1324 insertions, 0 deletions
diff --git a/node_modules/emittery/index.d.ts b/node_modules/emittery/index.d.ts new file mode 100644 index 0000000..37da6a1 --- /dev/null +++ b/node_modules/emittery/index.d.ts @@ -0,0 +1,432 @@ +/** +Emittery accepts strings and symbols as event names. + +Symbol event names can be used to avoid name collisions when your classes are extended, especially for internal events. +*/ +type EventName = string | symbol; + +// Helper type for turning the passed `EventData` type map into a list of string keys that don't require data alongside the event name when emitting. Uses the same trick that `Omit` does internally to filter keys by building a map of keys to keys we want to keep, and then accessing all the keys to return just the list of keys we want to keep. +type DatalessEventNames<EventData> = { + [Key in keyof EventData]: EventData[Key] extends undefined ? Key : never; +}[keyof EventData]; + +declare const listenerAdded: unique symbol; +declare const listenerRemoved: unique symbol; +type OmnipresentEventData = {[listenerAdded]: Emittery.ListenerChangedData; [listenerRemoved]: Emittery.ListenerChangedData}; + +/** +Emittery is a strictly typed, fully async EventEmitter implementation. Event listeners can be registered with `on` or `once`, and events can be emitted with `emit`. + +`Emittery` has a generic `EventData` type that can be provided by users to strongly type the list of events and the data passed to the listeners for those events. Pass an interface of {[eventName]: undefined | <eventArg>}, with all the event names as the keys and the values as the type of the argument passed to listeners if there is one, or `undefined` if there isn't. + +@example +``` +import Emittery = require('emittery'); + +const emitter = new Emittery< + // Pass `{[eventName: <string | symbol>]: undefined | <eventArg>}` as the first type argument for events that pass data to their listeners. + // A value of `undefined` in this map means the event listeners should expect no data, and a type other than `undefined` means the listeners will receive one argument of that type. + { + open: string, + close: undefined + } +>(); + +// Typechecks just fine because the data type for the `open` event is `string`. +emitter.emit('open', 'foo\n'); + +// Typechecks just fine because `close` is present but points to undefined in the event data type map. +emitter.emit('close'); + +// TS compilation error because `1` isn't assignable to `string`. +emitter.emit('open', 1); + +// TS compilation error because `other` isn't defined in the event data type map. +emitter.emit('other'); +``` +*/ +declare class Emittery< + EventData = Record<string, any>, // When https://github.com/microsoft/TypeScript/issues/1863 ships, we can switch this to have an index signature including Symbols. If you want to use symbol keys right now, you need to pass an interface with those symbol keys explicitly listed. + AllEventData = EventData & OmnipresentEventData, + DatalessEvents = DatalessEventNames<EventData> +> { + /** + Fires when an event listener was added. + + An object with `listener` and `eventName` (if `on` or `off` was used) is provided as event data. + + @example + ``` + import Emittery = require('emittery'); + + const emitter = new Emittery(); + + emitter.on(Emittery.listenerAdded, ({listener, eventName}) => { + console.log(listener); + //=> data => {} + + console.log(eventName); + //=> '🦄' + }); + + emitter.on('🦄', data => { + // Handle data + }); + ``` + */ + static readonly listenerAdded: typeof listenerAdded; + + /** + Fires when an event listener was removed. + + An object with `listener` and `eventName` (if `on` or `off` was used) is provided as event data. + + @example + ``` + import Emittery = require('emittery'); + + const emitter = new Emittery(); + + const off = emitter.on('🦄', data => { + // Handle data + }); + + emitter.on(Emittery.listenerRemoved, ({listener, eventName}) => { + console.log(listener); + //=> data => {} + + console.log(eventName); + //=> '🦄' + }); + + off(); + ``` + */ + static readonly listenerRemoved: typeof listenerRemoved; + + /** + In TypeScript, it returns a decorator which mixins `Emittery` as property `emitteryPropertyName` and `methodNames`, or all `Emittery` methods if `methodNames` is not defined, into the target class. + + @example + ``` + import Emittery = require('emittery'); + + @Emittery.mixin('emittery') + class MyClass {} + + const instance = new MyClass(); + + instance.emit('event'); + ``` + */ + static mixin( + emitteryPropertyName: string | symbol, + methodNames?: readonly string[] + ): <T extends { new (): any }>(klass: T) => T; // eslint-disable-line @typescript-eslint/prefer-function-type + + /** + Subscribe to one or more events. + + Using the same listener multiple times for the same event will result in only one method call per emitted event. + + @returns An unsubscribe method. + + @example + ``` + import Emittery = require('emittery'); + + const emitter = new Emittery(); + + emitter.on('🦄', data => { + console.log(data); + }); + emitter.on(['🦄', '🐶'], data => { + console.log(data); + }); + + emitter.emit('🦄', '🌈'); // log => '🌈' x2 + emitter.emit('🐶', '🍖'); // log => '🍖' + ``` + */ + on<Name extends keyof AllEventData>( + eventName: Name, + listener: (eventData: AllEventData[Name]) => void | Promise<void> + ): Emittery.UnsubscribeFn; + + /** + Get an async iterator which buffers data each time an event is emitted. + + Call `return()` on the iterator to remove the subscription. + + @example + ``` + import Emittery = require('emittery'); + + const emitter = new Emittery(); + const iterator = emitter.events('🦄'); + + emitter.emit('🦄', '🌈1'); // Buffered + emitter.emit('🦄', '🌈2'); // Buffered + + iterator + .next() + .then(({value, done}) => { + // done === false + // value === '🌈1' + return iterator.next(); + }) + .then(({value, done}) => { + // done === false + // value === '🌈2' + // Revoke subscription + return iterator.return(); + }) + .then(({done}) => { + // done === true + }); + ``` + + In practice you would usually consume the events using the [for await](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/for-await...of) statement. In that case, to revoke the subscription simply break the loop. + + @example + ``` + import Emittery = require('emittery'); + + const emitter = new Emittery(); + const iterator = emitter.events('🦄'); + + emitter.emit('🦄', '🌈1'); // Buffered + emitter.emit('🦄', '🌈2'); // Buffered + + // In an async context. + for await (const data of iterator) { + if (data === '🌈2') { + break; // Revoke the subscription when we see the value `🌈2`. + } + } + ``` + + It accepts multiple event names. + + @example + ``` + import Emittery = require('emittery'); + + const emitter = new Emittery(); + const iterator = emitter.events(['🦄', '🦊']); + + emitter.emit('🦄', '🌈1'); // Buffered + emitter.emit('🦊', '🌈2'); // Buffered + + iterator + .next() + .then(({value, done}) => { + // done === false + // value === '🌈1' + return iterator.next(); + }) + .then(({value, done}) => { + // done === false + // value === '🌈2' + // Revoke subscription + return iterator.return(); + }) + .then(({done}) => { + // done === true + }); + ``` + */ + events<Name extends keyof EventData>( + eventName: Name | Name[] + ): AsyncIterableIterator<EventData[Name]>; + + /** + Remove one or more event subscriptions. + + @example + ``` + import Emittery = require('emittery'); + + const emitter = new Emittery(); + + const listener = data => console.log(data); + (async () => { + emitter.on(['🦄', '🐶', '🦊'], listener); + await emitter.emit('🦄', 'a'); + await emitter.emit('🐶', 'b'); + await emitter.emit('🦊', 'c'); + emitter.off('🦄', listener); + emitter.off(['🐶', '🦊'], listener); + await emitter.emit('🦄', 'a'); // nothing happens + await emitter.emit('🐶', 'b'); // nothing happens + await emitter.emit('🦊', 'c'); // nothing happens + })(); + ``` + */ + off<Name extends keyof AllEventData>( + eventName: Name, + listener: (eventData: AllEventData[Name]) => void | Promise<void> + ): void; + + /** + Subscribe to one or more events only once. It will be unsubscribed after the first + event. + + @returns The event data when `eventName` is emitted. + + @example + ``` + import Emittery = require('emittery'); + + const emitter = new Emittery(); + + emitter.once('🦄').then(data => { + console.log(data); + //=> '🌈' + }); + emitter.once(['🦄', '🐶']).then(data => { + console.log(data); + }); + + emitter.emit('🦄', '🌈'); // Logs `🌈` twice + emitter.emit('🐶', '🍖'); // Nothing happens + ``` + */ + once<Name extends keyof AllEventData>(eventName: Name): Promise<AllEventData[Name]>; + + /** + Trigger an event asynchronously, optionally with some data. Listeners are called in the order they were added, but executed concurrently. + + @returns A promise that resolves when all the event listeners are done. *Done* meaning executed if synchronous or resolved when an async/promise-returning function. You usually wouldn't want to wait for this, but you could for example catch possible errors. If any of the listeners throw/reject, the returned promise will be rejected with the error, but the other listeners will not be affected. + */ + emit<Name extends DatalessEvents>(eventName: Name): Promise<void>; + emit<Name extends keyof EventData>( + eventName: Name, + eventData: EventData[Name] + ): Promise<void>; + + /** + Same as `emit()`, but it waits for each listener to resolve before triggering the next one. This can be useful if your events depend on each other. Although ideally they should not. Prefer `emit()` whenever possible. + + If any of the listeners throw/reject, the returned promise will be rejected with the error and the remaining listeners will *not* be called. + + @returns A promise that resolves when all the event listeners are done. + */ + emitSerial<Name extends DatalessEvents>(eventName: Name): Promise<void>; + emitSerial<Name extends keyof EventData>( + eventName: Name, + eventData: EventData[Name] + ): Promise<void>; + + /** + Subscribe to be notified about any event. + + @returns A method to unsubscribe. + */ + onAny( + listener: ( + eventName: keyof EventData, + eventData: EventData[keyof EventData] + ) => void | Promise<void> + ): Emittery.UnsubscribeFn; + + /** + Get an async iterator which buffers a tuple of an event name and data each time an event is emitted. + + Call `return()` on the iterator to remove the subscription. + + In the same way as for `events`, you can subscribe by using the `for await` statement. + + @example + ``` + import Emittery = require('emittery'); + + const emitter = new Emittery(); + const iterator = emitter.anyEvent(); + + emitter.emit('🦄', '🌈1'); // Buffered + emitter.emit('🌟', '🌈2'); // Buffered + + iterator.next() + .then(({value, done}) => { + // done is false + // value is ['🦄', '🌈1'] + return iterator.next(); + }) + .then(({value, done}) => { + // done is false + // value is ['🌟', '🌈2'] + // revoke subscription + return iterator.return(); + }) + .then(({done}) => { + // done is true + }); + ``` + */ + anyEvent(): AsyncIterableIterator< + [keyof EventData, EventData[keyof EventData]] + >; + + /** + Remove an `onAny` subscription. + */ + offAny( + listener: ( + eventName: keyof EventData, + eventData: EventData[keyof EventData] + ) => void | Promise<void> + ): void; + + /** + Clear all event listeners on the instance. + + If `eventName` is given, only the listeners for that event are cleared. + */ + clearListeners(eventName?: keyof EventData): void; + + /** + The number of listeners for the `eventName` or all events if not specified. + */ + listenerCount(eventName?: keyof EventData): number; + + /** + Bind the given `methodNames`, or all `Emittery` methods if `methodNames` is not defined, into the `target` object. + + @example + ``` + import Emittery = require('emittery'); + + const object = {}; + + new Emittery().bindMethods(object); + + object.emit('event'); + ``` + */ + bindMethods(target: Record<string, unknown>, methodNames?: readonly string[]): void; +} + +declare namespace Emittery { + /** + Removes an event subscription. + */ + type UnsubscribeFn = () => void; + + /** + The data provided as `eventData` when listening for `Emittery.listenerAdded` or `Emittery.listenerRemoved`. + */ + interface ListenerChangedData { + /** + The listener that was added or removed. + */ + listener: (eventData?: unknown) => void | Promise<void>; + + /** + The name of the event that was added or removed if `.on()` or `.off()` was used, or `undefined` if `.onAny()` or `.offAny()` was used. + */ + eventName?: EventName; + } +} + +export = Emittery; diff --git a/node_modules/emittery/index.js b/node_modules/emittery/index.js new file mode 100644 index 0000000..293b664 --- /dev/null +++ b/node_modules/emittery/index.js @@ -0,0 +1,408 @@ +'use strict'; + +const anyMap = new WeakMap(); +const eventsMap = new WeakMap(); +const producersMap = new WeakMap(); +const anyProducer = Symbol('anyProducer'); +const resolvedPromise = Promise.resolve(); + +const listenerAdded = Symbol('listenerAdded'); +const listenerRemoved = Symbol('listenerRemoved'); + +function assertEventName(eventName) { + if (typeof eventName !== 'string' && typeof eventName !== 'symbol') { + throw new TypeError('eventName must be a string or a symbol'); + } +} + +function assertListener(listener) { + if (typeof listener !== 'function') { + throw new TypeError('listener must be a function'); + } +} + +function getListeners(instance, eventName) { + const events = eventsMap.get(instance); + if (!events.has(eventName)) { + events.set(eventName, new Set()); + } + + return events.get(eventName); +} + +function getEventProducers(instance, eventName) { + const key = typeof eventName === 'string' || typeof eventName === 'symbol' ? eventName : anyProducer; + const producers = producersMap.get(instance); + if (!producers.has(key)) { + producers.set(key, new Set()); + } + + return producers.get(key); +} + +function enqueueProducers(instance, eventName, eventData) { + const producers = producersMap.get(instance); + if (producers.has(eventName)) { + for (const producer of producers.get(eventName)) { + producer.enqueue(eventData); + } + } + + if (producers.has(anyProducer)) { + const item = Promise.all([eventName, eventData]); + for (const producer of producers.get(anyProducer)) { + producer.enqueue(item); + } + } +} + +function iterator(instance, eventNames) { + eventNames = Array.isArray(eventNames) ? eventNames : [eventNames]; + + let isFinished = false; + let flush = () => {}; + let queue = []; + + const producer = { + enqueue(item) { + queue.push(item); + flush(); + }, + finish() { + isFinished = true; + flush(); + } + }; + + for (const eventName of eventNames) { + getEventProducers(instance, eventName).add(producer); + } + + return { + async next() { + if (!queue) { + return {done: true}; + } + + if (queue.length === 0) { + if (isFinished) { + queue = undefined; + return this.next(); + } + + await new Promise(resolve => { + flush = resolve; + }); + + return this.next(); + } + + return { + done: false, + value: await queue.shift() + }; + }, + + async return(value) { + queue = undefined; + + for (const eventName of eventNames) { + getEventProducers(instance, eventName).delete(producer); + } + + flush(); + + return arguments.length > 0 ? + {done: true, value: await value} : + {done: true}; + }, + + [Symbol.asyncIterator]() { + return this; + } + }; +} + +function defaultMethodNamesOrAssert(methodNames) { + if (methodNames === undefined) { + return allEmitteryMethods; + } + + if (!Array.isArray(methodNames)) { + throw new TypeError('`methodNames` must be an array of strings'); + } + + for (const methodName of methodNames) { + if (!allEmitteryMethods.includes(methodName)) { + if (typeof methodName !== 'string') { + throw new TypeError('`methodNames` element must be a string'); + } + + throw new Error(`${methodName} is not Emittery method`); + } + } + + return methodNames; +} + +const isListenerSymbol = symbol => symbol === listenerAdded || symbol === listenerRemoved; + +class Emittery { + static mixin(emitteryPropertyName, methodNames) { + methodNames = defaultMethodNamesOrAssert(methodNames); + return target => { + if (typeof target !== 'function') { + throw new TypeError('`target` must be function'); + } + + for (const methodName of methodNames) { + if (target.prototype[methodName] !== undefined) { + throw new Error(`The property \`${methodName}\` already exists on \`target\``); + } + } + + function getEmitteryProperty() { + Object.defineProperty(this, emitteryPropertyName, { + enumerable: false, + value: new Emittery() + }); + return this[emitteryPropertyName]; + } + + Object.defineProperty(target.prototype, emitteryPropertyName, { + enumerable: false, + get: getEmitteryProperty + }); + + const emitteryMethodCaller = methodName => function (...args) { + return this[emitteryPropertyName][methodName](...args); + }; + + for (const methodName of methodNames) { + Object.defineProperty(target.prototype, methodName, { + enumerable: false, + value: emitteryMethodCaller(methodName) + }); + } + + return target; + }; + } + + constructor() { + anyMap.set(this, new Set()); + eventsMap.set(this, new Map()); + producersMap.set(this, new Map()); + } + + on(eventNames, listener) { + assertListener(listener); + + eventNames = Array.isArray(eventNames) ? eventNames : [eventNames]; + for (const eventName of eventNames) { + assertEventName(eventName); + getListeners(this, eventName).add(listener); + + if (!isListenerSymbol(eventName)) { + this.emit(listenerAdded, {eventName, listener}); + } + } + + return this.off.bind(this, eventNames, listener); + } + + off(eventNames, listener) { + assertListener(listener); + + eventNames = Array.isArray(eventNames) ? eventNames : [eventNames]; + for (const eventName of eventNames) { + assertEventName(eventName); + getListeners(this, eventName).delete(listener); + + if (!isListenerSymbol(eventName)) { + this.emit(listenerRemoved, {eventName, listener}); + } + } + } + + once(eventNames) { + return new Promise(resolve => { + const off = this.on(eventNames, data => { + off(); + resolve(data); + }); + }); + } + + events(eventNames) { + eventNames = Array.isArray(eventNames) ? eventNames : [eventNames]; + for (const eventName of eventNames) { + assertEventName(eventName); + } + + return iterator(this, eventNames); + } + + async emit(eventName, eventData) { + assertEventName(eventName); + + enqueueProducers(this, eventName, eventData); + + const listeners = getListeners(this, eventName); + const anyListeners = anyMap.get(this); + const staticListeners = [...listeners]; + const staticAnyListeners = isListenerSymbol(eventName) ? [] : [...anyListeners]; + + await resolvedPromise; + await Promise.all([ + ...staticListeners.map(async listener => { + if (listeners.has(listener)) { + return listener(eventData); + } + }), + ...staticAnyListeners.map(async listener => { + if (anyListeners.has(listener)) { + return listener(eventName, eventData); + } + }) + ]); + } + + async emitSerial(eventName, eventData) { + assertEventName(eventName); + + const listeners = getListeners(this, eventName); + const anyListeners = anyMap.get(this); + const staticListeners = [...listeners]; + const staticAnyListeners = [...anyListeners]; + + await resolvedPromise; + /* eslint-disable no-await-in-loop */ + for (const listener of staticListeners) { + if (listeners.has(listener)) { + await listener(eventData); + } + } + + for (const listener of staticAnyListeners) { + if (anyListeners.has(listener)) { + await listener(eventName, eventData); + } + } + /* eslint-enable no-await-in-loop */ + } + + onAny(listener) { + assertListener(listener); + anyMap.get(this).add(listener); + this.emit(listenerAdded, {listener}); + return this.offAny.bind(this, listener); + } + + anyEvent() { + return iterator(this); + } + + offAny(listener) { + assertListener(listener); + this.emit(listenerRemoved, {listener}); + anyMap.get(this).delete(listener); + } + + clearListeners(eventNames) { + eventNames = Array.isArray(eventNames) ? eventNames : [eventNames]; + + for (const eventName of eventNames) { + if (typeof eventName === 'string' || typeof eventName === 'symbol') { + getListeners(this, eventName).clear(); + + const producers = getEventProducers(this, eventName); + + for (const producer of producers) { + producer.finish(); + } + + producers.clear(); + } else { + anyMap.get(this).clear(); + + for (const listeners of eventsMap.get(this).values()) { + listeners.clear(); + } + + for (const producers of producersMap.get(this).values()) { + for (const producer of producers) { + producer.finish(); + } + + producers.clear(); + } + } + } + } + + listenerCount(eventNames) { + eventNames = Array.isArray(eventNames) ? eventNames : [eventNames]; + let count = 0; + + for (const eventName of eventNames) { + if (typeof eventName === 'string') { + count += anyMap.get(this).size + getListeners(this, eventName).size + + getEventProducers(this, eventName).size + getEventProducers(this).size; + continue; + } + + if (typeof eventName !== 'undefined') { + assertEventName(eventName); + } + + count += anyMap.get(this).size; + + for (const value of eventsMap.get(this).values()) { + count += value.size; + } + + for (const value of producersMap.get(this).values()) { + count += value.size; + } + } + + return count; + } + + bindMethods(target, methodNames) { + if (typeof target !== 'object' || target === null) { + throw new TypeError('`target` must be an object'); + } + + methodNames = defaultMethodNamesOrAssert(methodNames); + + for (const methodName of methodNames) { + if (target[methodName] !== undefined) { + throw new Error(`The property \`${methodName}\` already exists on \`target\``); + } + + Object.defineProperty(target, methodName, { + enumerable: false, + value: this[methodName].bind(this) + }); + } + } +} + +const allEmitteryMethods = Object.getOwnPropertyNames(Emittery.prototype).filter(v => v !== 'constructor'); + +Object.defineProperty(Emittery, 'listenerAdded', { + value: listenerAdded, + writable: false, + enumerable: true, + configurable: false +}); +Object.defineProperty(Emittery, 'listenerRemoved', { + value: listenerRemoved, + writable: false, + enumerable: true, + configurable: false +}); + +module.exports = Emittery; diff --git a/node_modules/emittery/license b/node_modules/emittery/license new file mode 100644 index 0000000..fa7ceba --- /dev/null +++ b/node_modules/emittery/license @@ -0,0 +1,9 @@ +MIT License + +Copyright (c) Sindre Sorhus <sindresorhus@gmail.com> (https://sindresorhus.com) + +Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: + +The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. + +THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. diff --git a/node_modules/emittery/package.json b/node_modules/emittery/package.json new file mode 100644 index 0000000..2390cba --- /dev/null +++ b/node_modules/emittery/package.json @@ -0,0 +1,66 @@ +{ + "name": "emittery", + "version": "0.8.1", + "description": "Simple and modern async event emitter", + "license": "MIT", + "repository": "sindresorhus/emittery", + "funding": "https://github.com/sindresorhus/emittery?sponsor=1", + "author": { + "name": "Sindre Sorhus", + "email": "sindresorhus@gmail.com", + "url": "https://sindresorhus.com" + }, + "engines": { + "node": ">=10" + }, + "scripts": { + "test": "xo && nyc ava && tsd" + }, + "files": [ + "index.js", + "index.d.ts" + ], + "keywords": [ + "event", + "emitter", + "eventemitter", + "events", + "async", + "emit", + "on", + "once", + "off", + "listener", + "subscribe", + "unsubscribe", + "pubsub", + "tiny", + "addlistener", + "addeventlistener", + "dispatch", + "dispatcher", + "observer", + "trigger", + "await", + "promise", + "typescript", + "ts", + "typed" + ], + "devDependencies": { + "@types/node": "^13.7.5", + "ava": "^2.4.0", + "delay": "^4.3.0", + "nyc": "^15.0.0", + "p-event": "^4.1.0", + "tsd": "^0.14.0", + "xo": "^0.36.1" + }, + "nyc": { + "reporter": [ + "html", + "lcov", + "text" + ] + } +} diff --git a/node_modules/emittery/readme.md b/node_modules/emittery/readme.md new file mode 100644 index 0000000..2b419b0 --- /dev/null +++ b/node_modules/emittery/readme.md @@ -0,0 +1,409 @@ +# <img src="media/header.png" width="1000"> + +> Simple and modern async event emitter + +[](https://codecov.io/gh/sindresorhus/emittery) +[](https://bundlephobia.com/result?p=emittery) + +It works in Node.js and the browser (using a bundler). + +Emitting events asynchronously is important for production code where you want the least amount of synchronous operations. Since JavaScript is single-threaded, no other code can run while doing synchronous operations. For Node.js, that means it will block other requests, defeating the strength of the platform, which is scalability through async. In the browser, a synchronous operation could potentially cause lags and block user interaction. + +## Install + +``` +$ npm install emittery +``` + +## Usage + +```js +const Emittery = require('emittery'); + +const emitter = new Emittery(); + +emitter.on('🦄', data => { + console.log(data); +}); + +const myUnicorn = Symbol('🦄'); + +emitter.on(myUnicorn, data => { + console.log(`Unicorns love ${data}`); +}); + +emitter.emit('🦄', '🌈'); // Will trigger printing '🌈' +emitter.emit(myUnicorn, '🦋'); // Will trigger printing 'Unicorns love 🦋' +``` + +## API + +### eventName + +Emittery accepts strings and symbols as event names. + +Symbol event names can be used to avoid name collisions when your classes are extended, especially for internal events. + +### emitter = new Emittery() + +#### on(eventName | eventName[], listener) + +Subscribe to one or more events. + +Returns an unsubscribe method. + +Using the same listener multiple times for the same event will result in only one method call per emitted event. + +```js +const Emittery = require('emittery'); + +const emitter = new Emittery(); + +emitter.on('🦄', data => { + console.log(data); +}); +emitter.on(['🦄', '🐶'], data => { + console.log(data); +}); + +emitter.emit('🦄', '🌈'); // log => '🌈' x2 +emitter.emit('🐶', '🍖'); // log => '🍖' +``` + +##### Custom subscribable events + +Emittery exports some symbols which represent custom events that can be passed to `Emitter.on` and similar methods. + +- `Emittery.listenerAdded` - Fires when an event listener was added. +- `Emittery.listenerRemoved` - Fires when an event listener was removed. + +```js +const Emittery = require('emittery'); + +const emitter = new Emittery(); + +emitter.on(Emittery.listenerAdded, ({listener, eventName}) => { + console.log(listener); + //=> data => {} + + console.log(eventName); + //=> '🦄' +}); + +emitter.on('🦄', data => { + // Handle data +}); +``` + +###### Listener data + +- `listener` - The listener that was added. +- `eventName` - The name of the event that was added or removed if `.on()` or `.off()` was used, or `undefined` if `.onAny()` or `.offAny()` was used. + +Only events that are not of this type are able to trigger these events. + +##### listener(data) + +#### off(eventName | eventName[], listener) + +Remove one or more event subscriptions. + +```js +const Emittery = require('emittery'); + +const emitter = new Emittery(); + +const listener = data => console.log(data); +(async () => { + emitter.on(['🦄', '🐶', '🦊'], listener); + await emitter.emit('🦄', 'a'); + await emitter.emit('🐶', 'b'); + await emitter.emit('🦊', 'c'); + emitter.off('🦄', listener); + emitter.off(['🐶', '🦊'], listener); + await emitter.emit('🦄', 'a'); // Nothing happens + await emitter.emit('🐶', 'b'); // Nothing happens + await emitter.emit('🦊', 'c'); // Nothing happens +})(); +``` + +##### listener(data) + +#### once(eventName | eventName[]) + +Subscribe to one or more events only once. It will be unsubscribed after the first event. + +Returns a promise for the event data when `eventName` is emitted. + +```js +const Emittery = require('emittery'); + +const emitter = new Emittery(); + +emitter.once('🦄').then(data => { + console.log(data); + //=> '🌈' +}); +emitter.once(['🦄', '🐶']).then(data => { + console.log(data); +}); + +emitter.emit('🦄', '🌈'); // Log => '🌈' x2 +emitter.emit('🐶', '🍖'); // Nothing happens +``` + +#### events(eventName) + +Get an async iterator which buffers data each time an event is emitted. + +Call `return()` on the iterator to remove the subscription. + +```js +const Emittery = require('emittery'); + +const emitter = new Emittery(); +const iterator = emitter.events('🦄'); + +emitter.emit('🦄', '🌈1'); // Buffered +emitter.emit('🦄', '🌈2'); // Buffered + +iterator + .next() + .then(({value, done}) => { + // done === false + // value === '🌈1' + return iterator.next(); + }) + .then(({value, done}) => { + // done === false + // value === '🌈2' + // Revoke subscription + return iterator.return(); + }) + .then(({done}) => { + // done === true + }); +``` + +In practice, you would usually consume the events using the [for await](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/for-await...of) statement. In that case, to revoke the subscription simply break the loop. + +```js +const Emittery = require('emittery'); + +const emitter = new Emittery(); +const iterator = emitter.events('🦄'); + +emitter.emit('🦄', '🌈1'); // Buffered +emitter.emit('🦄', '🌈2'); // Buffered + +// In an async context. +for await (const data of iterator) { + if (data === '🌈2') { + break; // Revoke the subscription when we see the value '🌈2'. + } +} +``` + +It accepts multiple event names. + +```js +const Emittery = require('emittery'); + +const emitter = new Emittery(); +const iterator = emitter.events(['🦄', '🦊']); + +emitter.emit('🦄', '🌈1'); // Buffered +emitter.emit('🦊', '🌈2'); // Buffered + +iterator + .next() + .then(({value, done}) => { + // done === false + // value === '🌈1' + return iterator.next(); + }) + .then(({value, done}) => { + // done === false + // value === '🌈2' + // Revoke subscription + return iterator.return(); + }) + .then(({done}) => { + // done === true + }); +``` + +#### emit(eventName, data?) + +Trigger an event asynchronously, optionally with some data. Listeners are called in the order they were added, but executed concurrently. + +Returns a promise that resolves when all the event listeners are done. *Done* meaning executed if synchronous or resolved when an async/promise-returning function. You usually wouldn't want to wait for this, but you could for example catch possible errors. If any of the listeners throw/reject, the returned promise will be rejected with the error, but the other listeners will not be affected. + +#### emitSerial(eventName, data?) + +Same as above, but it waits for each listener to resolve before triggering the next one. This can be useful if your events depend on each other. Although ideally they should not. Prefer `emit()` whenever possible. + +If any of the listeners throw/reject, the returned promise will be rejected with the error and the remaining listeners will *not* be called. + +#### onAny(listener) + +Subscribe to be notified about any event. + +Returns a method to unsubscribe. + +##### listener(eventName, data) + +#### offAny(listener) + +Remove an `onAny` subscription. + +#### anyEvent() + +Get an async iterator which buffers a tuple of an event name and data each time an event is emitted. + +Call `return()` on the iterator to remove the subscription. + +```js +const Emittery = require('emittery'); + +const emitter = new Emittery(); +const iterator = emitter.anyEvent(); + +emitter.emit('🦄', '🌈1'); // Buffered +emitter.emit('🌟', '🌈2'); // Buffered + +iterator.next() + .then(({value, done}) => { + // done === false + // value is ['🦄', '🌈1'] + return iterator.next(); + }) + .then(({value, done}) => { + // done === false + // value is ['🌟', '🌈2'] + // Revoke subscription + return iterator.return(); + }) + .then(({done}) => { + // done === true + }); +``` + +In the same way as for `events`, you can subscribe by using the `for await` statement + +#### clearListeners(eventNames?) + +Clear all event listeners on the instance. + +If `eventNames` is given, only the listeners for that events are cleared. + +#### listenerCount(eventNames?) + +The number of listeners for the `eventNames` or all events if not specified. + +#### bindMethods(target, methodNames?) + +Bind the given `methodNames`, or all `Emittery` methods if `methodNames` is not defined, into the `target` object. + +```js +import Emittery = require('emittery'); + +const object = {}; + +new Emittery().bindMethods(object); + +object.emit('event'); +``` + +## TypeScript + +The default `Emittery` class has generic types that can be provided by TypeScript users to strongly type the list of events and the data passed to their event listeners. + +```ts +import Emittery = require('emittery'); + +const emitter = new Emittery< + // Pass `{[eventName]: undefined | <eventArg>}` as the first type argument for events that pass data to their listeners. + // A value of `undefined` in this map means the event listeners should expect no data, and a type other than `undefined` means the listeners will receive one argument of that type. + { + open: string, + close: undefined + } +>(); + +// Typechecks just fine because the data type for the `open` event is `string`. +emitter.emit('open', 'foo\n'); + +// Typechecks just fine because `close` is present but points to undefined in the event data type map. +emitter.emit('close'); + +// TS compilation error because `1` isn't assignable to `string`. +emitter.emit('open', 1); + +// TS compilation error because `other` isn't defined in the event data type map. +emitter.emit('other'); +``` + +### Emittery.mixin(emitteryPropertyName, methodNames?) + +A decorator which mixins `Emittery` as property `emitteryPropertyName` and `methodNames`, or all `Emittery` methods if `methodNames` is not defined, into the target class. + +```ts +import Emittery = require('emittery'); + +@Emittery.mixin('emittery') +class MyClass {} + +const instance = new MyClass(); + +instance.emit('event'); +``` + +## Scheduling details + +Listeners are not invoked for events emitted *before* the listener was added. Removing a listener will prevent that listener from being invoked, even if events are in the process of being (asynchronously!) emitted. This also applies to `.clearListeners()`, which removes all listeners. Listeners will be called in the order they were added. So-called *any* listeners are called *after* event-specific listeners. + +Note that when using `.emitSerial()`, a slow listener will delay invocation of subsequent listeners. It's possible for newer events to overtake older ones. + +## FAQ + +### How is this different than the built-in `EventEmitter` in Node.js? + +There are many things to not like about `EventEmitter`: its huge API surface, synchronous event emitting, magic error event, flawed memory leak detection. Emittery has none of that. + +### Isn't `EventEmitter` synchronous for a reason? + +Mostly backwards compatibility reasons. The Node.js team can't break the whole ecosystem. + +It also allows silly code like this: + +```js +let unicorn = false; + +emitter.on('🦄', () => { + unicorn = true; +}); + +emitter.emit('🦄'); + +console.log(unicorn); +//=> true +``` + +But I would argue doing that shows a deeper lack of Node.js and async comprehension and is not something we should optimize for. The benefit of async emitting is much greater. + +### Can you support multiple arguments for `emit()`? + +No, just use [destructuring](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Destructuring_assignment): + +```js +emitter.on('🦄', ([foo, bar]) => { + console.log(foo, bar); +}); + +emitter.emit('🦄', [foo, bar]); +``` + +## Related + +- [p-event](https://github.com/sindresorhus/p-event) - Promisify an event by waiting for it to be emitted |